This invention relates to variable plug two-dimensional nozzles of a jet engine and particularly to means for sealing at the interface of the movable plug and side wall, which side wall is fabricated from Finwall.RTM. material.
Because of the hostile environment in which the variable plug operates, cooling of the component parts are necessary. One such method of cooling is described in a U.S. patent application Ser. No. 751,428 filed on Dec. 16, 1976 by John H. Young and Gerald F. Goetz. One feature of the cooling system is the incorporation of Finwall constructed wall which provides a core of passages which permits the flow of cooling air so that the cooling air is in indirect heat exchange relationship at the skin surfaces of the parts exposed to the flow of the engine's exhaust. Many segments make up the Finwall constructed walls such that the cooling flow exiting into the engine's exhaust stream vents through slots along the outer skin of the wall to form a film of cooling air.
In a thrust vectoring, variable area two-dimensional nozzle, the plug is articulated to move to form certain configurations defining optimum aircraft performance characteristics, as described, for example, in U.S. Pat. No. 3,774,868 granted on Nov. 27, 1973, incorporated herein by reference. As noted in U.S. Pat. No. 3,774,868, supra, it will be appreciated that the panels of the plug move relative to the adjacent side walls. In the cooling scheme contemplated, the plug is pressurized with cooler air to some value higher than the corresponding pressure of the engine's exhaust adjacent the outer panel walls and thus when slotted Finwall constructed side walls are utilized an excessive leakage path is envisioned. Without appropriate sealing means, the use of Finwall constructed walls would not be possible to meet the design criteria for this application.
We have found that we can solve this leakage problem by judiciously spaced dam-like barriers disposed in each of the vent slots in the wall where the adjacent panel is articulated. This permits the plug to slide over the slots and in any given position a dam-like element will serve to prevent excessive leakage of the cooling air, and allowing the use of a Finwall constructed wall and its attendant cooling features.